AstraZeneca's $1.3B gout drug comes under EU scrutiny

The European Medicines Agency has accepted AstraZeneca's ($AZN) application for lesinurad, a gout treatment with a checkered efficacy record, stoking the company's hopes that it can make the drug into a blockbuster.

The EMA's nod kicks off a formal review process for lesinurad, acquired in AstraZeneca's $1.3 billion acquisition of Ardea Biosciences in 2013, and next the agency's Committee for Medicinal Products for Human Use will weigh in on whether to approve it as an addition to standard gout therapy. The drug is a selective uric acid reabsorption inhibitor that blocks the URAT1 transporter, treating the painful condition by normalizing acid excretion and reducing serum levels.

And, in three Phase III trials, lesinurad has proven adept at doing just that, meeting its primary endpoints by effectively slashing the uric acid that can lead to painful gout flare-ups. The problem, AstraZeneca disclosed last year, is that lesinurad failed to beat out generic allopurinol in actually reducing the number of reported gout exacerbations, a secondary goal in two of its pivotal studies. Thus, AstraZeneca can tout lesinurad as excellent at improving an accepted biomarker for gout but not so impressive at treating the effects that matter to patients.

However, the company contends that measuring gout flares in clinical trials is problematic at best, as many take place outside the clinic and are difficult to capture in efficacy data. Between 40% and 80% of gout patients can't get to physician-recommended uric acid levels on standard therapies alone, AstraZeneca said, creating what the company believes is a serious unmet medical need.

Whether that will resonate with regulators remains to be seen. And, if the drug eventually passes EMA and FDA muster, AstraZeneca could run into trouble convincing payers to shell out for a new therapy without clear evidence of improvement over the 50-year-old generic allopurinol and Takeda and Ipsen's ($IPN) febuxostat, approved in 2009.

AstraZeneca omitted lesinurad when it outlined blue-sky sales figures for its pipeline candidates last year, but analysts have said the drug could wend its way to blockbuster status thanks to the global rise of gout.

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